Four grades. No spin.
ModerateControlled human trialsRepeated studies in people point the same way.
EarlySmall / lab / animalPromising signals, but not yet proven in people.
TraditionalLong-usedCenturies of use; clinical evidence still anecdotal.
NoneNo trials foundWe looked and found none. We won’t pretend otherwise.
Tea Tree
Moderate22 studies in our databaseIn controlled trials a 5% tea-tree gel cut acne lesions about as well as benzoyl peroxide — with less dryness. Eight acne studies make it our best-evidenced oil.
Peppermint
Moderate18 studies in our databaseTopical menthol eased tension-type headache and stimulated a tired scalp in small controlled studies.
Headache
A systematic review and a controlled trial give moderate evidence that menthol can ease tension headache.
PubMed →Hair growth
In a mouse study, 3% peppermint oil grew hair more effectively than minoxidil — striking, but animal-only.
PubMed →Fungal
Lab studies show peppermint and menthol have antifungal activity.
PubMed →Skin ageing
A controlled study found peppermint leaf extract improved dermal thickness.
PubMed →Rosemary
Early21 studies in our databaseLong used for hair and scalp. Early studies are promising — one small trial even matched 2% minoxidil for regrowth — but the evidence base is still limited.
Hair & thinning
One pharmaceutical-grade trial compared rosemary to minoxidil — promising, evidence still small.
PubMed →Dandruff
Superior antifungal action against dandruff-linked microbes in lab studies.
PubMed →Joints
Rosemary's carnosic acid showed anti-inflammatory activity in animal studies.
PubMed →Headache
Long used traditionally; clinical evidence still anecdotal.
PubMed →Argan
Early18 studies in our databaseRich in vitamin E and traditionally prized for skin. Early studies point to better hydration and elasticity; more research is needed.
Diaper rash
A 140-infant study found argan oil more effective than 1% hydrocortisone for diaper rash.
PubMed →Dry skin
A lab study showed argan oil improved skin hydration and barrier repair.
PubMed →Hair & thinning
Lab evidence suggests argan extracts support hair-cell growth and cut oxidative stress.
PubMed →Skin ageing
A review discusses argan's anti-ageing potential via antioxidant pathways.
PubMed →Vitamin E
Early22 studies in our databaseA well-known antioxidant. Topical evidence is still early and mixed — and we grade it that way, honestly.
Jojoba
NoneA superb carrier oil with a long traditional history — but, honestly, no clinical trials behind its claims.
We searched our research database and found no clinical trials for jojoba’s effects. It’s an excellent carrier oil — it mirrors skin’s own sebum, which is why it sits so well on oily, breakout-prone skin — and it’s prized in traditional care. But we won’t cite efficacy we don’t have.
Deep dives: read the full evidence per oil — Rosemary · Moroccan Argan · Cold-Press Jojoba · Peppermint.
Study counts reflect our internal research database (235+ studies across the range). Figures are honest tallies, not marketing claims; individual uses link to PubMed.