There any many in the scientific community who feel that dietary Soy may alone, when consumed consistently, be enough to halt the progression of, or prevent MPB

Soy May Help Men Protect Against Baldness, Prostate Cancer and Heart Disease

      There are some identified mechanisms behind Soy Isoflavone consumption that make this a plausible assertion. 

      Prior studies have shown that the mere consumption of Soy protein modestly reduces blood levels of DHT.

Soy Isoflavones Lower Serum DHT

      Another study in mammals revealed that Soy Isoflavones, when combined with Green Tea, reduce blood levels of DHT by approximately 80%, which is a greater reduction than finasteride, (Proscar/Propecia) which reduces DHT by 65%. 

      Soy Isoflavones, also facilitate the production of Equol, a Soy metabolite that handcuffs DHT, and prevents its effects on both hair and prostate function. Since a high proportion in Asian countries are heavy Soy consumers and genetic equol producers, that is thought to at least partially explain the significantly lower incidence of Androgenetic Alopecia in these cultures. 

Soy Metabolite Could Halt Hairloss(Male Pattern Baldness)

      The following study though, shows that dietary Soy alone is associated with a decreased incidence of MPB, across the board, without being an exclusive benefit to genetic Equol producers only.

      Oral Soy Isoflavones also have an overall firming effect on facial skin, and reduce the depth of surface wrinkles.

Soy Isoflavones for Hair Loss and Skin Aging

PLoS One. 2013 Dec 30;8(12):e79789.
Androgenic alopecia is associated with less dietary soy, lower [corrected] blood vanadium and rs1160312 1 polymorphism in Taiwanese communities.
Abstract
BACKGROUND:

Although the genetic basis of androgenic alopecia has been clearly established, little is known about its non-genetic causes, such as environmental and lifestyle factors.

OBJECTIVE:
This study investigated blood and urine heavy metals concentrations, environmental exposure factors, personal behaviors, dietary intakes and the genotypes of related susceptibility genes in patients with androgenic alopecia (AGA).

DESIGN:
Age, AGA level, residence area, work hours, sleep patterns, cigarette usage, alcohol consumption, betel nut usage, hair treatments, eating habits, body heavy metals concentrations and rs1998076, rs913063, rs1160312 and rs201571 SNP genotype data were collected from 354 men. Logistic regression analysis was performed to examine whether any of the factors displayed odds ratios (ORs) indicating association with moderate to severe AGA (≥ IV). Subsequently, Hosmer-Lemeshow, Nagelkerke R(2) and accuracy tests were conducted to help establish an optimal model.

RESULTS:
Moderate to severe AGA was associated with the AA genotype of rs1160312 (22.50, 95% CI 3.99-126.83), blood vanadium concentration (0.02, 95% CI 0.01-0.04), and regular consumption of soy bean drinks (0.23, 95% CI 0.06-0.85), after adjustment for age. The results were corroborated by the Hosmer-Lemeshow test (P = 0.73), Nagelkerke R(2) (0.59), accuracy test (0.816) and area under the curve (AUC; 0.90, 0.847-0.951) analysis.

CONCLUSIONS:
Blood vanadium and frequent soy bean drink consumption may provide protect effects against AGA. Accordingly, blood vanadium concentrations, the AA genotype of rs1160312 and frequent consumption of soy bean drinks are inversely associated with AGA.

      To obtain the health and hair benefits of Soy consumption, it is not necessary to consume tofu or Soy Protein (I don’t care for the taste of either). A potent oral Isoflavones supplement will give you far more benefits, and is more cost effective. 

      Although there is a borderline hysterical anti-soy camp, the vast preponderance of continually published evidence points to Soy having a tremendous array of benefits for human health. 

Literature Review: Soy NOT Feminizing, Beneficial for Hair