Cistanche tubulosa and Laminaria japonica have been reported to have anti-oxidative, anticoagulant, anti-cancer and anti-inflammatory properties. They are expected to be a promising candidates for promoting hair growth and treating dandruff and scalp inflammation as a consequence. In this double-blinded, placebo-controlled clinical trial, we investigated the efficacy of Cistanche tubulosa extract and Laminaria japonica extract complex (MK-R7) in promoting hair health in patients with mild to moderate patterned hair loss. Using phototrichogram (Folliscope 4.0, LeadM, Seoul, Korea), we compared the density and diameter of hairs in patients receiving a placebo or Cistanche tubulosa extract and Laminaria japonica extract complex (MK-R7) at baseline, 8 and 16 weeks of the study. In order to determine the efficacy of treatment on dandruff and scalp inflammation, investigator's assessment score and patient's subjective score were also performed. We found a statistically significant increase in the hair density of the test group (n = 45, MK-R7 400 mg) after 16 weeks of consuming the MK-R7 (test group: 23.29 n/cm² ± 24.26, control: 10.35 n/cm² ± 20.08, p < 0.05). In addition, we found a statistically significant increase in hair diameter in the test group compared to control group at week 16 (test group: 0.018 mm ± 0.015, control: 0.003 mm ± 0.013, p < 0.05). There were also significant outcomes regarding the investigator's visual assessment and patient's subjective score of dandruff and scalp inflammation in the test group compared to those in control group. Based on the results of this clinical study, we conclude that Cistanche tubulosa extract and Laminaria japonica extract complex (MK-R7) are promising substances for promoting health of the scalp and hair.