Shukra Dhatu (शुक्र धातुः)
Shukra Dhatu is one of the 7 body tissues as per Ayurveda. It is the 7th dhatu in Sharira according to Ayurveda. Since it is developed last i.e. at the end of dhatu development and nourishment pathway, it is called as 7th or the last dhatu. Shukra literally means semen, sperm, clear, lucid, white or spotless. Since Shukra dhatu develops at the end of rigorous metabolic transformations occurring during development of all 7 dhatus it is more clear or spotless.
The term shukra originates from the root word "शुच क्लेदे + “ऋज्रे न्द्राग्रवज्रेति ।”
In Ayurveda literature, 2 types of shukra dhatu can be found to be mentioned. One Shukra dhatu is that which is ejaculated at the end of mating and which is responsible for conception. The other form of shukra dhatu is also mentioned in treatises, which refers to the body tissue that is present in every part of shariram (physical body) and controls the rebuilding of body tissues, new cell/tissue generation and overall development. Thus the dhatu which controls the function of reproduction in the body is called as shukra dhatu.
Location of Shukra Dhatu
Shukra dhatu is present all over the body as stated by Acharya Charaka.
सर्वदेहगतं शुक्रं प्रवदन्ति मनीषिणः| (Char. Samh. 15.26)
There are some other body parts which are specifically mentioned to be the related to Shukra dhatu. Those are Vrishana (testicles), Medhra (Penis), Stana (Breasts). Also, vessels carrying shukra dhatu have also been mentioned to be associated with transportation of shukra.
Formation of shukra dhatu
Shukra dhatu is formed from 'Majja dhatu'(धातु). When Majja dhatu is subjected to the process of micro-transformation (सूक्ष्मपचनम्), one processed part of it is specifically utilized to provide nourishment to the next dhatu in order i.e. Shukra Dhatu (रक्त धातु). This part is responsible for development and nourishment of Shukra dhatu in body. Transformation of unctuous part of predecessor majja into Shukra happens through a specific process. It is stated that, the asthi dhatu develops porosity due to action of vayu and akasha mahabhutas. The unctuous part of majja dhatu present inside this porous asthi dhatu oozes out of these pores and reaches all parts of the body through channels of transportation of shukra dhatu (shukravahasrotas). This unctuous part is called as shukra. After puberty, at the time of sexual excitation or urge of ejaculation (vega), the semen (shukra) reaches to basti from all over the body and then is discharged through urethra. This process happens just like ghee is melted by heat.
Upadhatu of Shukra dhatu
Ojas is considered as the metabolic byproduct (upadhatu) of shukra.[Sha. Sa. Purva khanda chapter 5] Other scholars opine that as shukra is the essence of all dhatu, there is no metabolic byproduct or waste formed during its formation.
Mala of Shukra dhatu
scholars opine that as shukra is the essence of all dhatu, there is no metabolic byproduct or waste formed during its formation.
Qualities of best shukra
The best qualities of Shukra dhatu which is ejaculated out during the process of mating plays the key role in reproduction. Certain qualities of shukra which are helpful in reproduction are known to be best qualities of shukra. The Shukra which is unctuous (snigdha), viscous (ghana), slimy (picchila), sweet (madhura) and looks like white crystal quartz is considered to be a good quality shukra. 
Panchabhoutiktwa of Shukra dhatu
Among 5 mahabhutas, Shukra is believed to have dominance of 4 mahabhutas viz Vayu, Agni, Jalam and Prthvi.
Shukra sarata lakshanas
The persons endowed with the essence of shukra dhatu are gentle (saumya), having charming appearance (saumyaprekshina), beautiful eyes as if filled with milk (kshirapurnalochana) and immensely exhilarated (praharshabahula). Their teeth are unctuous, rounded, firm, even and compact. They have prominent buttocks (large pelvic girdle). They have pleasant, unctuous complexion and voice. They are brilliant. They are liked by women for enjoyment, are strong and endowed with happiness, leisure, health, wealth, honor, and progeny. [Cha. Sa. Vimana Sthana 8/109]
Function of shukra dhatu
Shukra bestows courage, ejaculation, lust, strength of the body, pleasure, love, and affection. The main function of shukra is reproduction and embryogenesis. [Su. Sa. Sutra Sthana 15/5]
Causes of vitiation
Causes of vitiation
The following are the causative factors for the vitiation of channels for transport and transformation of shukra dhatu.[Cha. Sa. Vimana Sthana 5/19]
Consumption of incompatible food, excessive consumption of dry, bitter, astringent, salty, sour, hot food.
Anxiety, distress, distrust, apprehension, rage, exorcism.
Causes related to coitus
Excess intercourse, untimely coitus, coitus other than in vagina, or complete abstinence from it(suppression of discharge of semen), unaware of female desire, untimely ejaculation etc.
Excess exercise, senility, improper usage of surgical instruments, alkali (kshara), heat or cautery (agni), emaciation due to other diseases, repression of natural urges, injury, morbidity causing vitiation of dhatus, doshas individually or collectively reaching reproductive system (retovahasrotas) leads to acute disorders of the shukra (semen). [Cha. Sa. Chikitsa Sthana 30/139]
Importance of Shukra dhatu in preservation of health and wellness
Aphrodisiac therapies (vajikarana) produces lineage of progeny, quick sexual stimulation, enables one to perform sexual act with the women uninterruptedly and promote corpulence and infallible and indestructible semen. [Cha. Sa. Chikitsa Sthana 1/1/9-10] This is one of the most important measures to promote sexual health and prevent diseases.
- Charaka Samhita (Chikitsasthanam Adhyaya 15 Sutram 26)
- Charaka Samhita (Vimanasthanam Adhyaya 5 Sutram 8)
- Sushruta Samhita (Sharirasthanam Adhyaya 9 Sutram 12)
- Charaka Samhita (Chikitsasthanam Adhyaya 15 Sutram 33-35)
- Charaka Samhita (Chikitsasthanam Adhyaya 30 Sutram 40)
- Charaka Samhita (Sharirasthanam Adhyaya 2 Sutram 4)