Harklinikken is a brand that has been around for 30 years, first opening as a hair clinic in Denmark, and now with a global presence that spans from Dubai to New York City. Harklinnikin offers a range of natural shampoos, conditioners, and creams, as well as a product called ‘Extract’ that they claim is  “customized to your individual requirements” and “free of harsh and toxic chemicals that can damage the scalp and lead to harmful side effects.” ^[1]Harklinikken, (no date). Extract, Available at: https://www.harklinikken.com/products/extract (Accessed: 21 December 2022) 

One of Harklinikken’s claims to fame is an endorsement from Ricki Lake, an actress and former talk show host who has recently opened up about her battle with androgenetic alopecia (AGA). Harklinikken diagnosed Ricki with AGA in 2020 before assigning her a treatment regime with multiple products, including the customized Extract product. ^[2]Harklinikken, (no date). Ricki Lake, Available at: https://www.harklinikken.com/pages/ricki-lake (Accessed: 21 December 2022) Ricki’s podcast is sponsored by Harklinikken, but she also encourages people to buy Harklinikken products on her personal social media and is also currently doing a giveaway promotion on her Instagram as ofthe time of writing. ^[3]Instagram, (2022), Ricki Lake. Available at: https://www.instagram.com/p/CmP7QAgPdcF/ (Accessed: 21 December 2022)

So, do Harklinikken’s products really work? Are the products clinically proven to regrow hair? And what, if anything, makes Harklinikken’s ‘Extract’ unique?

In this article, we’ll examine:

• Whether the Harklinikken ‘Extract’ is effective
• What the ingredients are and what the science behind them is (if there is any)
• If the product is worth the price point

Key Takeaways:

• • Branding: Harklinikken markets itself as a company that provides “high-quality, non-toxic and efficacious hair products” not just for people with hair thinning, but also for anyone “looking to make the most out of their hair”. ^[4]Harklinikken, (no date), About Harklinikken, Available at: https://www.harklinikken.com/pages/about-us (Accessed: 21 December 2022) 
  • Differentiation: Harklinikken differentiates itself from other products through its in-person and online clinics (through which you can use their Follysis software to quantify hair thickness and density), as well as its range of shampoos, conditioners, and its ‘Extract’ product. ‘Extract’ is a product they claim to be the “cornerstone of our tailored treatment regimens” which is “customized to your individual requirements”.
  • Clinical Support: Other than customer testimony and before-after photos there is no clinical support for any of their products. As for the ingredients in ‘Extract’ there have been no clinical trials in humans, although there have been some studies in cells and in mice indicating that there may be an effect for the burdock extract and the marigold extract, which can be included in their product.
  • Concerns: 
    • After 30 years and “more than 100,000 clients across the globe”, Harklinikken has undergone zero clinical trials for their ‘Extract’ product or the ingredients inside. ^[5]Harklinikken, (no date), Results. Available at: https://www.harklinikken.com/pages/hair-journeys (Accessed: 21 December 2022)
    • Publicly available data shows that there is little clinical support to indicate that the ingredients have an effect on hair follicle growth in humans.
    • Harklinikken seems to rely on the photos, reviews, and sponsorship with Ricki Lake to market their product rather than using scientific studies.
    • There is some evidence that topical benzoic acid, an ingredient in ‘Extract’ may stimulate the production of PGD2 which is known to contribute to androgenetic alopecia – however, as mentioned, there is sparse evidence that ‘Extract’ actually has a beneficial effect.
• Recommendations to the company:  Harklinekkin should invest in long-term, large-scale studies that include men and women to determine the efficacy and safety of their “Extract” product.
• Our current thoughts: At this price point, it is difficult to recommend Harklinikken’s ‘Extract’. However, if you can afford the steep price, want the experience of customization as well as check-ups, want to use a ‘natural’ product, and are happy using something for which there is little evidence of efficacy then this may be for you.

What is Harklinikken?

Harklinikken – which translates directly to hair clinic – is a Danish hair care brand.  They claim to sell “individual hair and scalp treatment regimes for each and every one of our clients”. ^[6]Harklinikken, (no date), It’s more than hair. Available at:https://www.harklinikken.com/pages/its-more-than-hair (Accessed 21 December 2022) The brand is now global, with clinics in Europe, the US, and Dubai, and has been around for 30 years. The founder and lead researcher of Harklinikken is  Lars Skjoth. Lars has a background in nutrition and biochemistry. ^[7]Instagram, (2019), Harklinikken. Available at: https://www.instagram.com/p/B1O9bfgAWPs/?hl=en (Accessed: 21 December 2022) He has spoken about his own hair loss issues saying “since childhood, I have been plagued with scalp and hair issues so it was natural for me to seek a career in this direction…”. ^[8]Harklinikken, (no date), About Us. Available at: https://www.harklinikken.com/pages/about-us (Accessed: 21 December 2022)

On the website, Lars says that the “products have been used by more than 100,000 people worldwide and have time-tested results” and that “The Extract is completely unique compared to other products for improving hair quality on the market today”. ^[9]Harklinikken, (no date), About Us. Available at: https://www.harklinikken.com/pages/about-us (Accessed: 21 December 2022)

Harklinikken clearly aims to put itself forward as a more ‘natural’ approach to hair care and treating hair loss, mentioning that its ‘Extract’ is “free of harsh and toxic chemicals that can damage the scalp and lead to harmful side effects”. ^[10]Harklinniken, (no date), Extract. Available at: https://www.harklinikken.com/products/extract (Accessed 21 December 2022)

Who is their Target Consumer?

Harklinikken states that: “since the start, we have helped thousands of men and women achieve their hair’s full and beautiful potential”. ^[11]Harklinikken, (no date), About us. Available at: https://www.harklinikken.com/pages/about-us (Accessed: 21 December 2022) In the before-and-after photos on Harkliniken’s website, however, there are only 3 photos of men whilst there are 34 photos of women indicating that women are the main market.

What products are offered by Harklinikken?

Harklinikken’s flagship product is simply called ‘Extract.’ This product has a customizable formula depending on the consumer’s hair assessment or an in-person visit at one of their clinics. This is their only customizable product, but they also offer a range of shampoos and conditioners, thickening creams, and styling products (Table 1). The criteria used in their ‘hair assessment’ are not clear.

What do they claim is unique about this product?

Harklinikken claims that their product, Extract, is unique as it is “100% customized and hand-blended to each client’s individual needs” and that the formula “is continually adjusted to ensure the best results aseach client progresses on his or her hair journey”. ^[12]Harklinikken, (no date), About Us. Available at: https://www.harklinikken.com/pages/about-us (Accessed: 21 December 2022) But how does Harklinikken achieve this level of personalization?

How does Harklinikken customize its products?

Harklinikken claims to tailor its products to each customer based on answers to customer surveys or through a specialist consultation. This online survey is quite long and is split into four categories: hair, scalp, hormones and genetics, and lifestyle. 

A selection of questions from each section are listed below. ^[13]Harklinikken, (no date), Hair assessment. Available at: https://www.harklinikken.com/pages/hair-assessment (Accessed: 21 December 2022):

HAIR

• How would you describe your hair?
  • Thin
  • Average 
  • Thick
• Which of these illustrations match how much scalp you see through your hair
• Have you noticed any of these changes in your hair?
  • Ponytail is thinner
  • Temple area becoming more visible
  • More fragile and prone to breakage/split ends
  • Middle part widening
  • More dry + dull
  • Loss of curls + increased frizz

SCALP

• How often do you feel that your scalp is dry, itchy, or tight?
  • Never
  • Rarely
  • Often
  • Always
• Have you recently noticed any severe redness or severe irritation on your scalp?
  • Yes
  • No
• How often do you shampoo per week?
  • Daily
  • Every 2nd day
  • Twice
  • Once or less

HORMONES AND GENETICS

• Are you pregnant or have given birth within the last 6 months
  • Yes
  • No
• Have you ever been diagnosed with any type of alopecia
  • Yes
  • No
• Are you currently undergoing (or have in the last 6 months) radiation, chemotherapy, or immunotherapy?
  • Yes
  • No

LIFESTYLE

• How stressed have you felt over the past 6 months?
  • Not feeling stressed
  • Moderately stressed
  • Highly stressed
  • Exceptionally stressed
• How many hours of sleep do you typically get per night?
  • More than 8 hours
  • Between 6-8 hours
  • Between 4-6 hours
  • Less than 4 hours
• Which best describes your typical diet?
  • Unhealthy
  • Balanced
  • Vegan
  • Ketogenic

Based on the responses to these questions, and from other questions in the survey, Harklinikken creates a bespoke formula within their ‘Extract’ product. This theoretically sounds great, as different types of hair loss surely will require different treatments. In principle, customization could improve hair loss outcomes as it would allow for a specific treatment catered to your specific requirement and helps to reduce time wasted (from a customer perspective) trying out products that may not be exactly what is needed for the specific type of hair loss you have.

The combination of quite a long, in-depth survey and the opportunity to speak with a specialist does give the impression that Harklinikken wants to get to the root of the problem and provide a bespoke product. However, there are some big questions left to ask, namely, do their products actually work?

Is there any clinical support for this product?

The simple answer to this question is no. There is no clinical support showing the efficacy of  Extract on their website or in any published trials. When we asked them if they had any journal articles that support their products, they directed us to the blogs and marketing posts on their website, which aren’t exactly peer-reviewed science or registered trials. 

Are there any before-and-after photos for this product?

Yes.

Harklinikken claims to have “+100,000 satisfied customers” and has provided 37 before-after photos. ^[14]Harklinikken, (no date), About Us. Available at: https://www.harklinikken.com/pages/about-us (Accessed 21 December 2022) However, most of these before-and-after pictures suffer from the usual problems when we try to interpret them: a different parting, hair pulled in a slightly different way, a change in hair color, or variations in lighting. This makes it difficult to really tell what the results are. One or two of the photos, however, show more notable (in my opinion) transformations (shown below).

Some of the other problems we have with just the before-and-after photos are that:

1. We don’t know the types of hair loss that the customers have
2. We don’t know if another medication is being taken alongside this treatment
3. We don’t know whether the hair grew back by itself or because of this product

Other than before-and-after photos, there is no concrete evidence of this product leading to hair growth.

Price points

Once you have gone through the hair assessment and signing-up process, you can either buy the recommended membership set or purchase individual items. The membership includes 2 bottles of ‘Extract,’ and one each of the shampoos and conditioners that they have determined is the most suitable based on your hair assessment results. You also receive an initial e-consultation (or in-person consultation if you are able to go to a clinic) with a so-called specialist and follow-up consultations (every 3 months). Membership is priced at $224. However, if you want to buy individual products or you need to top up after the membership pack runs out, then the products are priced as below.

Extract

$88 a month for 1 bottle, which gives a one-month supply, or $149.60 for 2 bottles every 2 months with their subscription. 

Product	Size	One-time buy price	Subscription Price
Balancing Shampoo	13.53oz 8.45oz 2.54oz	$54 $38 $15	$45.90 $32.30 $12.75
Stabilizing Shampoo	13.53oz	$54	$45.90
Fortifying Shampoo	8.45oz	$44	$37.40
Restorative Shampoo	13.53oz	$68	$57.80
Daily Conditioner	9.81oz 2.54oz	$49 $15	$41.65 $12.75
Hair Hydrating Creme	9.81oz 2.54oz	$56 $22	$47.60 $18.70
Hair Mask	8.45oz 2.54oz	$56 $25	$47.60 $21.25
Weightless Conditioner	9.81oz	$49	$41.65

Table 1: Adapted from: ^[17]Harklinikken, (no date), Shop. Available at: https://www.harklinikken.com/collections/hair-hydration/products/weightless-conditioner (Accessed: 21 December 2022)

If you want to also get an initial consultation, it will cost non-members $150 for an in-person consultation or $50 for an online consultation.

In our opinions, products at these price-points should be well-supported by clinical evidence. However, in our company investigation, we did not find any published clinical studies evaluating Harklinikken’s Extract product as a whole. Nonetheless, we can still perform a scientific analysis with the ingredients they publicly disclose, and see which ones might show clinical support for hair regrowth.

Product Science: Deep Dive

Harklinikken doesn’t have a full ingredient list for their Extract. However, they do mention that it “contains proprietary ingredients derived from burdock root, marigold, apple, sandalwood, and cow’s milk, alongside naturally occurring sterols, tannins and fatty acids found in botanicals”. ^[18]Harklinikken, (no date), Extract. Available at: https://www.harklinikken.com/products/extract (Accessed: 21 December 2022) 

So, we sent them a message asking about what ingredients could go into the Harklinikken custom ‘Extract’. Here’s their reply:

Let’s review some of the ingredients and discuss their possible effect on scalp/hair health and growth. It’s important to note that none of these ingredients are unique to Harklinikken’s Extract, and you can buy any of them separately.

Arctium Lappa extract

The common name for Arctium Lappa is burdock. Burdock is a plant that is native to Europe and Asia and has been introduced to North America. ^[19]Britannica, (no date), Burdock. Available at: https://www.britannica.com/plant/burdock (Accessed: 21 December 2022)

Burdock extracts have been used in medicines around the world and have properties as a diuretic (alters water retention), an antipyretic (reduces fever), and have also been used to treat many diseases such as high blood pressure and gout. ^[21]Chan, Y.S., Cheng, L.N., Wu, J.H., Chan, E., Kwan, Y.W., Lee, S.M.Y., Leung, G.P.H., Yu, P.H.F., Chan, S.W. (2011). A review of the pharmacological effects of Arctium Lappa (burdock). … Continue reading

These properties are due to the presence of lignans (compounds found in many plants that have antioxidant properties) as well as other antioxidants and small amounts of vitamins and minerals such as B1 (thiamine), through to B6 (pyridoxine), and iron, magnesium, calcium, etc. 

Arctiin, a lignan found in burdock, has been found to protect human dermal papilla cells against senescence (deterioration) induced by reactive oxygen species (ROS) and hydrogen peroxide in an in vitro study (study performed in cells/in a dish). ^[22]Bae, S., Lim, K.M., Cha, J.H., An, I.S., Lee, J.P., Lee, K.S., Lee, G.T., Lee, K.K., Jung, H.J., Ahn, K.J., An, S. (2014), Arctiin blocks hydrogen peroxide-induced senescence and cell death through … Continue reading Dermal papilla cells are specialized cells found in the bulb of the hair follicle that are critical for hair growth and cycling.

ROS are highly reactive chemicals formed as a natural by-product of processes within the cell. ^[23]Sies, H., Jones, D.P. (2020), Reactive oxygen species (ROS) as pleiotropic physiological signalling agents.  Nature reviews molecular cell biology. 21, 363-383. Available at: … Continue reading High concentrations of these can cause damage to cells and lead to senescence, in which cell processes don’t work in the way that they should. This study indicates that burdock extracts that contain this lignan may have a beneficial effect on the dermal papillae of hair follicles. However, there have been no clinical studies to date.

Beta-sitosterol is also found in burdock and is a chemical known as a plant sterol, which is similar to cholesterol. It is found in fruits, vegetables, nuts, and seeds and is thought to be a 5-alpha-reductase inhibitor. ^[24]Zamani, P., Mokhtari, O., Dehghanian, F. (2021), Identification of Beta-Sitosterol and Stigmasterol as Possible Inhibitors of 5 Alpha-Reductase 1: An In-Silico Study. Precision Medicine and Clinical … Continue reading Other 5-alpha-reductase inhibitors include finasteride (the only approved hair loss therapy for men) and dutasteride. These are also known as dihydrotestosterone (DHT) blockers. DHT is a chemical that has been found to be elevated in people with androgenetic alopecia (AGA). Therefore, beta-sitosterol may operate through the same biochemical pathway that is targeted by approved hair loss therapeutics like finasteride. 

A small study in 2002 investigated the efficacy of beta-sitosterol in treating hair loss. This study completed a randomized, double-blind, placebo-controlled trial on 19 male participants between the ages of 23 to 64 over 4 to 6 months. ^[25]Prager, N., Bickett, K., French., N., Marcovici, G. (2002). A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-α-reductase in … Continue reading 

Split into two groups, participants either took a capsule containing a combination of saw palmetto and sitosterol or a placebo capsule. These were taken twice daily. Dosages were: 50mg of beta-sitosterol and 200mg of saw palmetto per capsule. The results were based on the investigators’ opinions of improvement in hair density as well as self-assessment from the study participants. Investigators rated a 60% improvement in hair density for the treated group compared to the placebo group’s 11% improvement. Furthermore, participants who were in the treated group reported no deterioration of their bald spot (meaning that the bald spot did not get bigger), whereas 33% of the placebo group did report deterioration.

There are a few issues with this study, the main one being that the treated group was taking a combination treatment of saw palmetto and sitosterol, so it’s not possible to know where the positive effects of the treatment were coming from. Furthermore, there were no error bars added to the graphs, and the investigator assessments on hair density were completed by eye rather than through less subjective methods such as using a trichogram. This is where an area is shaved and then photos are taken during an experiment using a microscope. Hairs are then counted in the photographed area.

Whilst this study is interesting there is not enough clinical evidence yet to suggest that sitosterol is an effective treatment for hair loss.

So, is burdock extract effective at treating hair loss? While there is some evidence to suggest that components within burdock can have an effect, there is a significant lack of solid clinical data. Furthermore, even if there was a lot of data supporting this, you can buy burdock root, extract, or oil online for a far cheaper price than what you would be paying here.

Calendula officinalis Extract 

Calendula officinalis is also known as the plant pot marigold. Pot marigold extracts have many pharmacological properties including being anti-inflammatory, antimicrobial, and immunomodulatory. Furthermore, there have been reports of topical Calendula extract assisting in woundhealing. ^[28]Leach, M.J. (2008), Calendula officinalis and wound healing: a systematic review. Wounds. Available at: https://www.hmpgloballearningnetwork.com/site/wounds/article/9064 (Accessed: 21 December 2022) 

A chemical called quercetin, which is found in pot marigold, has been linked to hair follicle growth through its anti-inflammatory and antioxidant properties. Quercetin is known as a flavonoid, a group of naturally occurring chemicals that often have properties benefitting overall health. ^[30]Panche, A.N., Diwan, A.D., Chandra, S.R. (2016). Flavonoids: an overview. Journal of Nutritional Science. 5. 1-15. Available at: https://doi.org/10.1017/jns.2016.41

A study using mice that underwent spontaneous development of alopecia areata found that compared to the placebo group, mice treated with 100ml of 10M quercetin for 8 days (once daily injections) showed regrowth of hair after 6 weeks, whereas the placebo-treated mice showed no regrowth (although this is only based on photos rather than quantitative data).

Furthermore, they found that when simultaneously treating the mice with quercetin and inducing alopecia areata, none of the quercetin-treated group showed any hair loss. ^[32]Wikramanayake, T.C., Villasante, A.C., Mauro, L.M., Perez, C.I., Schachner, L.A., Jimenez, J.J. (2012). Prevention and treatment of alopecia areata with quercetin in the C3H/HeJ mouse model. Cell … Continue reading 

Another study has also found that quercetin treatment can stimulate melanogenesis (the formation of pigmentation) in mice, indicating further possible effects of quercetin on hair follicles. ^[33]Takekoshi, S., Matsuzaki, K., Kitatani, K. (2013). Quercetin stimulates melanogenesis in hair follicle melanocyte of the mouse. The Tokai Journal of Experimental and Clinical Medicine. 38(4). … Continue reading

Studies on mice, however, do not always transfer well to a human model, so is there any clinical data on how quercetin affects hair growth in humans? The answer is no. Quercetin is, however, used in multiple other treatments, and it, alongside calendula extract, is available to buy online, so if you want to integrate it into your routine, it should be safe for you to do so.

Other Ingredients

The other ingredients in ‘Extract’ are most likely used for skin hydration and as antimicrobials. Cera alba is beeswax, cetyl palmitate is an emollient, and citric acid balances pH. Pyrus malus fruit extract can have many uses in cosmetic products, including as a skin toner, a stabilizer, and a fragrance ingredient. ^[34]Cosmetics Info, (no date), Pyrus Malus (apple) fruit extract. Available at: https://www.cosmeticsinfo.org/ingredients/pyrus-malus-apple-fruit-extract/ (Accessed: 21 December 2022)

It’s worth noting that topical benzoic acid has been found to increase the synthesis of prostaglandin D2 (PGD2) in human skin. However, this was a very small study that hasn’t been used to explicitly look athair loss. ^[35]Downard, C.D., Roberts, L.J., Morrow, J.D. Topical benzoic acid induces the increased biosynthesis of prostaglandin D2 in human skin in vivo. Clinical Pharmacology and Therapeutics. 57(4), 441-445. … Continue reading

PGD2 is a key inflammatory mediator and has been implicated as being at least partially responsible for male-pattern baldness. Elevated levels of PGD2 have been found to be elevated in the bald areas of men with partial hair loss and throughout the scalp in men with full hair loss due to male-pattern baldness. ^[36]Garza, L.A., Liu, Y., Alagesan, B., Lawson, J.A., Norberg, S.M., Loy, D.E., Zhao, T., Blatt, H.B., Stanton, D.C., Carrasco, L., Gurpreet, A., Fischer, S.M., Fitzgerald, G.A., Cotsarelis, G. … Continue reading

Celebrity Endorsement

Ricki Lake, an actress and former talk show host, has been very vocal about her struggles around hair loss and about how Harklinikken has helped her hair to regrow over the past few years. On her Instagram, she shows a side-by-side after one year of using Harklinikken (below), and the results do look very good. ^[37]Instagram, (2022), Ricki Lake. Available at: https://www.instagram.com/p/ChFQe9_rLF-/ (Accessed: 21 December 2022)

It is important to mention, however, that Ricki is being sponsored by Harklinikken at least in part, through her podcast, and she also frequently posts about Harklinikken products on her Instagram. We do not know whether this represents the full extent of the relationship between Ricki Lane and Harklinikken.

Is it safe?

There is no safety data for the product as a whole, unfortunately. Though considered to be safe topically, burdock may cause allergic reactions in people who are sensitive to herbs and flowers and may cause a rash. ^[39]Rxlist, (2021), Burdock. Available at: https://www.rxlist.com/burdock/supplements.htm (Accessed: 21 December 20222) Topical Calendula officinalis has been found to be tolerated well in multiple studies where it has been applied to wounded/burned skin with no adverse events. ^[40]Pittner.H., Langer.R. (2018). Assessment Report on Calendula officinalis L.,flos. European Medicines Agency. Available at: … Continue reading

Is it for me?

There isn’t anything new or unique about the ingredients within Harklinikken’s ‘Extract’ and you could buy all of the ingredients online if you wanted to. Whilst there is a small amount of scientific support for some of the ingredients to improve hair growth, these are limited to AGA and alopecia areata. Harklinikken themselves say that they “cannot help those with alopecia areata, alopecia universalis, alopecia totalis or other autoimmune hair loss or scalp disorders” further limiting the scope of people that are likely to find results using this product. ^[41]Harklinikken, (no date), Frequently Asked Questions. Available at: https://www.harklinikken.com/pages/faq (Accessed 21 December 2022)

The Extract might be for you if:

• You want to use more ‘natural’ products to treat your hair loss
• You don’t mind taking the risk on a product for which there is very little evidence of efficacy or safety
• You have AGA or another hair loss issue that doesn’t fall under the list above
• You can afford to pay the high costs associated with the product 
  

For others out there, you can likely find something less expensive out there with the same ingredients and similar levels of clinical support.