Retinoic acid is one of the retinoids, a catch-all name for a group of compounds related to vitamin A. With dermatologists on TikTok promoting the benefits of minoxidil in combination with retinoids as a revolutionary hair loss hack, we take an in-depth look at this trend. Where did it come from? What do studies on minoxidil and retinoic acid say? How does it work? Is it safe? Read our review of this TikTok trend to find out all need to know about minoxidil and retinoic acid for hair loss.
It started with dancing. Now, TikTok has evolved to become a multidimensional lifestyle app. Users now share food, beauty and investment hacks with audiences of millions.
Healthcare is no exception.
In the past few months, videos from dermatologists have been promoting a combination of minoxidil and retinoids as the latest hair loss hack. But can such a complex issue as hair loss be fully addressed in a short video? And are these claims backed by scientific evidence?
Read our guide to minoxidil and retinoic acid for hair loss and find out everything you need to know about this trend. To learn more about minoxidil for hair loss, read our comprehensive guide, here.
What are Retinoids and How Do They Relate to Hair Loss Treatment?
Retinoids, a group of compounds related to Vitamin A, have prominent role in skincare due to their properties in boosting collagen formation and promoting new blood vessels in the skin. Among these compounds, retinoic acid, or tretinoin, holds a unique place. It’s not only a potent skincare agent but could play a significant role in hair loss treatment when used in conjunction with minoxidil.
The Role of Retinoic Acid in Hair Loss Treatment
Retinoic acid, a prescription-strength retinoid, has been found effective in the treatment of hair loss. It enhances the therapeutic effect of minoxidil, a widely-used over-the-counter medication for hair loss. When the two are used together, several studies suggest they can significantly improve hair regrowth compared to using minoxidil alone.3-5
Different Forms of Retinoids: Over-the-Counter vs Prescription
There are different forms of retinoids available and they’re not all the same. Over-the-counter retinoids like retinol are milder and primarily used in cosmeceuticals. However, retinoic acid, which is about 20 times more potent than retinol2, is already in its active form and has a more significant effect. It is prescribed specifically by healthcare professionals for its therapeutic properties in skin conditions and now, is a new addition to hair loss treatment arsenal.
Can tretinoin and minoxidil boost hair growth?
There is some research to suggest that Minoxidil and retinoids, specifically tretinoin or retinol can combine to increase hair growth in patients with androgenetic alopecia (AGA). A 2019 study3 which found that retinoic acid could increase the effectiveness of minoxidil has been gaining traction online. The study tested 10 male and 10 female patients with AGA for their responsiveness to minoxidil. An area of the scalp was treated for five consecutive days with 0.1% tretinoin cream. On the sixth day, they were retested for minoxidil responsiveness. 43% of those that were initially non-responders to minoxidil became responders after 5 days of treatment with tretinoin.
In a 2007 clinical trial4, 31 male patients with AGA were treated with 5% minoxidil twice daily, or once daily 5% minoxidil plus 0.01% tretinoin. The study found that once a day minoxidil with tretinoin was equivalent to twice daily minoxidil alone.
In a preclinical study also from 20075, scalp samples were taken from ten healthy male volunteers and treated with different concentrations of retinol, minoxidil or a combination of the two. Minoxidil and retinol were found to enhance hair growth more effectively than minoxidil alone while retinol alone didn’t increase hair growth.
How do retinoic acid and minoxidil work together for hair loss?
The synergistic effect of retinoic acid and minoxidil seems to center around an enzyme called sulfotransferase, found in the outer layer of scalp follicles. It is responsible for converting minoxidil to minoxidil sulfate, which is around 14 times more potent than minoxidil6.
Researchers found that retinoic acid increased sulfotransferase levels in the follicles. This means more minoxidil is being converted into the active form, meaning non-responders could suddenly find that minoxidil works for them if combined with a retinoid.
This combination may also increase minoxidil absorption through tretinoin reducing the skin’s barrier function and lowering sebum levels, which is known to carry DHT, the key hormone behind AGA.
Does retinoic acid and minoxidil work for hair loss?
The available evidence suggests that a combination of retinoic acid and minoxidil can boost hair growth in patients with androgenetic alopecia. Scientists have shown that retinoic acid acts to boost sulfotransferase enzyme levels which could make minoxidil more effective.3 The same should apply to retinol but it’s likely to be less potent.
The evidence is compelling, but larger-scale research is needed to determine how effective this combination is and the optimum doses and concentrations to use.
There is no evidence to suggest that retinol and minoxidil work for other causes of hair loss, such as traction alopecia, or alopecia areata.
Can I use tretinoin with finasteride? Can I use tretinoin with dutasteride?
There’s no firm evidence that using retinoic acid or other retinoids with other hair loss treatments will boost hair growth. The boosting effect that retinoic acid has with minoxidil is due to its effect on sulfotransferase levels. Sulfotransferase does not affect 5-AR blockers like finasteride and dutasteride, as far as we know.
Some research suggests that retinoic acid could boost the effects of topical medications such as finasteride and dutasteride. This is because retinoic acid may increase skin permeability and increase drug absorption5. In theory, this could boost the effects of topical medications such as finasteride and dutasteride. Other researchers have noted that this explanation is unlikely, as retinoids can increase the thickness of the dermis3, making it harder for drugs to be absorbed.
For now, the jury is out on retinoic acid in combination with finasteride and dutasteride. While it could increase the absorption, it could also increase the potential for side effects.
How do I use retinoic acid and minoxidil to boost hair growth?
Because retinoic acid is a prescription medication, consult with your healthcare provider or a dermatologist to determine the best combination for your needs.
With retinol, which is available over the counter, the general advice is to start with the lowest concentration possible and go up from there, depending on the results or any side effects. Starting with a high-concentration retinol formula could lead to skin and scalp irritation so it’s best to gently introduce your skin to retinol.
Find an over-the-counter facial skincare product and apply it as directed to your face and hairline, usually only a couple of times a week to start with. If you already have a retinol-based product in your skin-care routine, use that instead of buying a new one but begin to include your hairline where your hair has receded
After you’ve applied the retinol, your skin will be highly sensitive to the sun, so you will need to wear a high SPF (30+) sunscreen and ideally avoid sun exposure.
You can apply your minoxidil as you normally would once the retinol has been absorbed.
What is the best concentration of retinoic acid for hair loss?
In studies examining tretinoin, the concentrations varied from 0.01% up to 0.1%. It’s still too early to say what the most effective concentration is. Tretinoin is available on prescription only, so you should discuss this with your healthcare provider or dermatologist.
What are the side effects of retinoids for hair loss?
The main side effects of topical retinoids are skin or scalp irritation, dryness, peeling and sensitivity to sunlight and temperature. In some cases, retinoids can lead to changes in skin tone, either lightening or darkening the skin.
Who can use retinoids and minoxidil for hair loss?
Topical retinoids such as retinoic acid can be used in combination with minoxidil by male and female patients with AGA. It is unlikely that you will see any positive results in other causes of hair loss, such as traction alopecia or stress-related telogen effluvium.
If you have sensitive skin or existing irritation on the scalp, avoid retinoids they can worsen things.
If you are pregnant, breastfeeding or planning on becoming pregnant, discuss the use of retinol-containing products with your healthcare provider before starting them.
Retinoic acid and minoxidil for hair loss: to sum up
The combined use of minoxidil and retinoic acid has grabbed the attention of both the healthcare community and the public, thanks to platforms like TikTok.
The evidence suggests promising outcomes for patients with AGA, but keeping a balanced perspective is vital.
The concept of boosting minoxidil’s efficacy with retinoic acid sounds exciting but larger-scale, controlled research is still necessary. What we do know is that retinoic acid is much more potent and is likely to be more effective than retinol, which is easily available but weaker and will take longer to show any positive results. Ideally, consult with a healthcare provider or dermatologist before starting new treatment combinations.
- Mukherjee S, Date A, Patravale V, Korting HC, Roeder A, Weindl G. Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clin Interv Aging. 2006;1(4):327-48. doi: 10.2147/ciia.2006.1.4.327. PMID: 18046911; PMCID: PMC2699641.
- Sharma A, Goren A, Dhurat R, Agrawal S, Sinclair R, Trüeb RM, Vañó-Galván S, Chen G, Tan Y, Kovacevic M, Situm M, McCoy J. Tretinoin enhances minoxidil response in androgenetic alopecia patients by upregulating follicular sulfotransferase enzymes. Dermatol Ther. 2019 May;32(3):e12915. doi: 10.1111/dth.12915. Epub 2019 Apr 23. PMID: 30974011.
- Shin HS, Won CH, Lee SH, Kwon OS, Kim KH, Eun HC. Efficacy of 5% minoxidil versus combined 5% minoxidil and 0.01% tretinoin for male pattern hair loss: a randomized, double-blind, comparative clinical trial. Am J Clin Dermatol. 2007;8(5):285-90. doi: 10.2165/00128071-200708050-00003. PMID: 17902730.
- Yoo HG, Chang IY, Pyo HK, Kang YJ, Lee SH, Kwon OS, Cho KH, Eun HC, Kim KH. The additive effects of minoxidil and retinol on human hair growth in vitro. Biol Pharm Bull. 2007 Jan;30(1):21-6. doi: 10.1248/bpb.30.21. PMID: 17202653.
- Dias PCR, Miot HA, Trüeb RM, Ramos PM. Use of Minoxidil Sulfate versus Minoxidil Base in Androgenetic Alopecia Treatment: Friend or Foe? Skin Appendage Disord. 2018 Oct;4(4):349-350. doi: 10.1159/000488011. Epub 2018 Apr 5. PMID: 30410915; PMCID: PMC6219241.