5 Reasons Why Japan’s Ama Divers Still Have Arms Like That at 75 (and the Seaweed American Women Now Press On After the Shower)

1. A woman of 75 stepped out of the Pacific with her arms full of seaweed, and I couldn't stop looking at her forearms

I'm Japanese-American, and my grandmother talked about the ama the way other grandmothers talk about saints. Last spring I finally went to Toba, in Mie Prefecture, to see them. The ama are women who dive for a living with no air tank, one held breath at a time, for abalone, sea urchin, turban shells and seaweed. Only about 2,000 are left in all of Japan, and roughly 750 of them work around Toba, about half. The tradition goes back some 2,000 years, and until around the 1970s they dove in plain white cotton, no wetsuit.

The one who stopped me was a diver of about 75, walking up the wet rocks at low tide on a cold April morning with a bundle of wakame dripping over her hand. What I noticed first wasn't the seaweed. It was her forearms: brown, strong, and smoother than I expected from a woman who has spent fifty-odd years in salt water, wind and sun. Many ama still dive in their 70s, and some are in the water into their 80s.

I'm not going to tell you the seaweed did that. Cold water, a lifetime of moving, a diet built on fish and sea vegetables and plain genetics all play a part. But I came home with a question I couldn't shake: what exactly was she holding, and why has nobody put it in the body care I buy at home? The next four reasons are the answer.

2. The brown seaweed in her hand is wakame, a sea plant skin researchers keep coming back to

Wakame (Undaria pinnatifida) is the silky brown seaweed in your miso soup. It grows in cold coastal water, and in Mie's bays it's gathered in late winter and spring when the sea is coldest. Like other brown algae, it's rich in two compounds with long names: fucoidan, a sulfated sugar, and fucoxanthin, the pigment that gives it that deep olive-brown color.

Here is what the science says, and what it doesn't. In a 2008 lab study in Biological and Pharmaceutical Bulletin, fucoidan from brown seaweed reduced the amount of MMP-1, an enzyme that breaks down collagen, that human skin cells made after UVB exposure. Later work in mice looked at fucoidan purified from Undaria pinnatifida itself and saw a similar pattern after UV exposure. These were skin cells in a dish and mice, not women's arms, and none of it tested a bottle of ADIRA. I'm telling you because they're the reason a skin chemist looks at this seaweed twice.

ADIRA's formula carries wakame as an extract, there for skin that has gone thin and crepey. Wakame is also the seaweed the ama of Mie gather by hand every spring. That overlap, a sea plant with a thousand-year story and a lab trail, is what made me stop and write this.

3. Why it isn't in the lotion on your nightstand: seaweed costs more than filler, so almost nobody puts it in an American body product

When I got home I did something simple. I stood in the lotion aisle of my local drugstore and turned bottles around. Twenty-some body lotions and creams, and I did not find wakame on a single label. What I found, over and over, was the same short list: glycerin, a thickener, a preservative, and “fragrance.”

A seaweed extract costs more than the filler that makes up most of a lotion, so it rarely makes the cut. Seaweed shows up all the time in Japanese and Korean skin care, and the French have a name for it, thalassotherapy, spa routines built around the sea. It just hasn't made it onto the big American body shelf.

So the arms that need the most help get the generic formula, and the one ingredient the ama's coast is known for never makes it to the bottle. That's the gap. The next two reasons are how women are closing it.

4. The 60-second ritual: warm shower, pat dry, two pumps, press in, get dressed

In Toba, after every dive the ama warm up in a little hut by a wood fire, the amagoya, and sit and talk for an hour. It's the opposite of a rushed routine, and it's the idea I borrowed. Here's the American, 60-second version.

Step 1: Shower, then pat dry so your skin is still a little damp. Step 2: Two or three pumps of ADIRA into your palm, warmed for a second. Step 3: Press it onto your forearms and upper arms, then the chest and the legs, and smooth it in until it's gone. It absorbs in about a minute, with no greasy residue, and you can get dressed right away. Arms, legs, chest: one minute.

Skin doesn't change overnight and I won't pretend otherwise. What readers describe is gradual: arms that feel soft and supple from the first days, and a smoother-looking texture by weeks 3–4. Nobody gets 30-year-old arms from a bottle. But the arms that used to catch on a cardigan sleeve start to look like they belong to you again.

“I'm 66. I started the shower ritual in September, and by week four my husband asked what I'd changed. I told him: the seaweed.” — Marlene, 66, Asheville, North Carolina

5. Why ADIRA put wakame into a waterless oil: 16 botanicals, zero water, $19.97 a bottle

ADIRA is an American brand, and I won't pretend it comes from Toba. What it did was take the seaweed idea and put it somewhere it doesn't get watered down: a body oil with no water. Wakame extract sits alongside Brazil nut oil, passionflower seed oil, rosehip, argan, squalane, jojoba, vitamin C and vitamin E, bisabolol and soft vanilla. Sixteen botanicals in all, from a seaweed of the Pacific to oils from the Amazon.

The offer is simple. 3 bottles are $59.90, or $19.97 a bottle (Buy 2, Get 1 Free), shipped free. One bottle on its own is $49.90, so the other two cost $10 more. Arms, legs and chest every day will empty a bottle faster than you expect, and three means you stop rationing it.

There's no subscription: you pay once and nothing is charged later. And if your skin doesn't look and feel better, you get a full refund within 90 days. The ama have their sea. You have your shower.