In terms of supplementation, there are few studies that look at omega-3 fatty acids and hair growth, and few that study fish oil in particular.
One small study in the February 2017 issue of the Journal of Clinical and Aesthetic Dermatology looked at 10 participants with androgenetic alopecia (known as male-pattern baldness, which can appear in men and women, notes MedlinePlus) who were each given a twice-daily supplement containing a mix of fish oil, flaxseed oil, antioxidants, and melatonin. After about six months, eight people (representing 80 percent of participants) had an increase in hair. It’s important to remember, though, that this was a very small study and there was no placebo group.
An earlier study, with 120 participants, was published in 2015 in the Journal of Cosmetic Dermatology. It compared a group taking a supplement containing fish oil and vitamins C and E (among other ingredients) with a control group. After six months, 62 percent of those in the supplement group saw an increase in hair density compared with 28 percent in the control group. What’s perhaps surprising is that more than half of the women in the control group said they noticed an increase in hair growth when comparing before and after photos of their scalp. “I really think we need more data and more research to understand the potential mechanism,” says Dr. Goldberg, who was not involved with either study.
Supplements may contain fish oil or omega-3s along with other ingredients, like antioxidants. These ingredients may act synergistically together, so we shouldn’t jump to the conclusion that taking fish oil or omega-3s alone in a supplement will grow hair.
As for topical application, a study published in September 2018 in the International Journal of Molecular Sciences, in which scientists applied a fermented mackerel oil topically to rodents’ whiskers, found that the substance helped stimulate follicles, possibly by activating the “growth” phase of hair.
That’s one study — and on rodents. Overall, “topical application of fish oil will not support hair growth or scalp health,” says Kerry Yates, a trichologist and the founder of Colour Collective in Dallas. It also has a fishy smell, and the lingering odor is enough to deter some people from using pure fish oil on the scalp.
When it comes to hair growth, the most effective option is to eat a healthy diet, use gentle hair-care products, and seek treatment (start with your dermatologist) if you are losing hair, so any health conditions can be addressed, says Goldberg.
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What Is the Best Form of Fish Oil?
There are many different ways you can get fish oil, including fish oil supplements, fish liver oil supplements (like cod liver oil), and shellfish and whole fish, according to the National Center for Complementary and Integrative Health (NCCIH). In terms of food, fatty or oily fish have the greatest amounts of omega-3s, such as salmon, sardines, mackerel, cod, herring, trout, and canned tuna, per the Mayo Clinic.
Fish like these provide a range of additional vitamins and minerals not found in supplements. To reap the potential benefits of fish oil, opt for whole fish over pills, registered dietitians recommend. If you are going to take a supplement for hair, skin, or nails, choose one that uses small fish to limit mercury levels, says Debra Jaliman, MD, a board-certified dermatologist in New York City and the author of Skin Rules. She likes Nordic Naturals, which uses fish oil from anchovies and sardines.
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Is Fish Oil Good for Your Hair and Nails?
There’s a lack of data showing the role of fish oil in hair and nail health. What’s most important is that you’re getting the omega-3s your body needs to function well all around. “Various vitamins [claiming] they can grow the hair will support any deficiencies you may have but will not guarantee hair growth,” says Yates.
If you are well nourished and eat a balanced diet, Goldberg says it’s unlikely you are deficient in omega-3s. “And, if you don’t have a deficiency, then it’s unclear whether taking more omega 3s than you need through a supplement will help,” says Goldberg.
Does Cod Liver Oil Cause Hair Loss?
There are no studies that show that cod liver oil causes hair loss — there is no research establishing a relationship between cod liver oil and tress health in general. But an excess of certain vitamins, such as vitamin A, may worsen hair loss, according to research published in the journal Dermatology Practical & Conceptual in January 2017. Cod liver oil contains EPA and DHA, as well as vitamins A and D, says the NCCIH. The organization warns that the amounts of these two vitamins vary from product to product. Some supplements may contain too much vitamin A, which may cause a problem for your health and your hair. It’s important to choose supplements from high-quality brands that your healthcare team has cleared.