# Mahasutra guides ## Perfume - [Fragrance Notes Explained: Top, Heart and Base Notes](https://mahasutra.co/journal/fragrance-notes-explained): Top, heart and base notes explained: the fragrance pyramid, why perfumes change on skin, key perfume terms, and how to test a scent properly. - [Does Perfume Expire? Shelf Life, Signs It's Gone Off and How to Store It](https://mahasutra.co/journal/does-perfume-expire): How long perfume lasts, what makes it go off, signs it has turned, why oxidised perfume can irritate skin, and how to store fragrance in hot climates. - [Sandalwood in Perfume: Indian, Australian and Synthetic Sandalwood Explained](https://mahasutra.co/journal/sandalwood-in-perfume): Sandalwood explained: Santalum album vs Australian and other species, santalol content, the Mysore story, synthetic sandalwood, and how to wear it. - [Parfum vs Eau de Parfum vs Eau de Toilette: Concentrations Explained](https://mahasutra.co/journal/parfum-vs-eau-de-parfum-vs-eau-de-toilette): Parfum, eau de parfum, eau de toilette and cologne explained: typical concentrations, how long each lasts, longevity vs projection, and how to choose. - [Perfume Oil vs Perfume Spray: Which Lasts Longer and Which to Choose](https://mahasutra.co/journal/perfume-oil-vs-perfume-spray): Perfume oil vs alcohol-based spray compared: projection, longevity, skin feel, heat and humidity, travel, and how to layer both. - [What Is Oud? Agarwood, How It Forms and Why It Costs So Much](https://mahasutra.co/journal/what-is-oud): Oud (agarwood) explained: how it forms in Aquilaria trees, what it smells like by origin, why it's expensive, CITES and cultivation, and oud accords. - [How to Make Perfume Last Longer in a Humid Climate](https://mahasutra.co/journal/how-to-make-perfume-last-longer-in-a-humid-climate): Heat and humidity change how perfume behaves — most advice online is written for temperate climates. What actually works in Southeast Asia. ## Essential oils - [Spikenard Essential Oil: Smell, Uses, Safety and Sustainability](https://mahasutra.co/journal/spikenard-essential-oil): What spikenard (jatamansi) essential oil smells like, how to use it in evening blends, what the research shows, safety, and why it is critically endangered. - [Valerian Root Essential Oil: Smell, Sleep Evidence and How to Use It](https://mahasutra.co/journal/valerian-root-essential-oil): Why valerian root oil smells so strong, what sleep studies actually tested, how to blend it into an evening routine, and who should avoid it. - [Ravintsara vs Ravensara: The Difference and Why It Matters](https://mahasutra.co/journal/ravintsara-vs-ravensara): Ravintsara (Cinnamomum camphora, cineole type) and ravensara (Ravensara aromatica) compared: chemistry, scent, safety and how to check what you're buying. - [Eucalyptus Radiata vs Globulus: Which Eucalyptus Oil to Choose](https://mahasutra.co/journal/eucalyptus-radiata-vs-globulus): Eucalyptus radiata and globulus compared: scent, cineole content, uses, which is gentler in blends, and the child-safety rule that applies to both. - [Essential Oils for a Blocked Nose: What Menthol and Eucalyptus Really Do](https://mahasutra.co/journal/essential-oils-for-blocked-nose): How menthol, eucalyptus and other oils affect a blocked nose, what the research shows, how to use a chest rub or steam safely, and when to see a doctor. - [Peppermint Oil for Headaches: What the Clinical Trials Show](https://mahasutra.co/journal/peppermint-oil-for-headaches): The clinical evidence for peppermint oil on tension headaches, how to apply it, which headaches it won't help, and who should avoid it. - [Rosemary Essential Oil for Focus and Memory: What the Research Shows](https://mahasutra.co/journal/rosemary-essential-oil-for-focus): The Northumbria University rosemary studies explained, what they do and don't prove, other oils for focus, and how to use scent at your desk. - [Essential Oils for Motion Sickness and Travel Nausea: Ginger, Peppermint and What Works](https://mahasutra.co/journal/essential-oils-for-motion-sickness): Ginger and peppermint for travel sickness: what the research shows for eating vs smelling them, a practical travel routine, and safety tips. - [Essential Oils for Sore Muscles: Menthol, Camphor and How Muscle Rubs Work](https://mahasutra.co/journal/essential-oils-for-sore-muscles): How cooling and warming muscle rubs work, the evidence for menthol, which essential oils are used, how to apply them, and important safety rules. - [Helichrysum (Immortelle) Essential Oil: What It Is, Why It's Costly and How to Use It](https://mahasutra.co/journal/helichrysum-essential-oil): Helichrysum italicum (immortelle) oil explained: origin, scent, chemistry, the evidence for skin, how to dilute it and how to avoid adulterated oil. - [Blue Tansy vs German Chamomile: Why They're Blue and How They Differ](https://mahasutra.co/journal/blue-tansy-vs-german-chamomile): Blue tansy and German chamomile compared: chamazulene, scent, chemistry, skin use, storage and safety, plus how they differ from Roman chamomile. - [Copaiba Oil: Beta-Caryophyllene, CB2 and What It Really Means](https://mahasutra.co/journal/copaiba-balsam-oil): Copaiba balsam oil explained: Amazonian origin, scent, beta-caryophyllene and the CB2 receptor, what the research does and doesn't show, and safety. - [Holy Basil (Tulsi) Essential Oil: Uses, Safety and How It Differs From Basil](https://mahasutra.co/journal/holy-basil-tulsi-essential-oil): Holy basil (tulsi) essential oil explained: scent, eugenol, the 1% skin limit, differences from sweet basil and tulsi tea, and blending ideas. - [Frankincense Essential Oil: Species, Boswellic Acids and Sustainable Sourcing](https://mahasutra.co/journal/frankincense-essential-oil): Frankincense oil explained: Boswellia species compared, why boswellic acids aren't in the essential oil, uses in perfume and wellbeing, and sustainability. - [Vetiver Essential Oil: Smell, Origins, Uses in Perfume and Wellbeing](https://mahasutra.co/journal/vetiver-essential-oil): Vetiver (khus) oil explained: scent, origins compared, its role in perfume, use in calming blends, safety and why it is one of the more sustainable oils. - [Essential Oil Dilution Chart: How Many Drops per 10 ml and 30 ml](https://mahasutra.co/journal/essential-oil-dilution-chart): Essential oil dilution chart with drops per 10, 30 and 50 ml, recommended strengths for face, body and massage, oils with lower limits, and patch testing. - [Are Essential Oils Safe for Cats and Dogs? Diffusers, Risks and Safe Use](https://mahasutra.co/journal/are-essential-oils-safe-for-pets): Why essential oils can poison cats, dogs and birds, signs of poisoning, what to do, and how to use diffusers and home fragrance safely with pets. - [10 Things You Should Never Do With Essential Oils](https://mahasutra.co/journal/10-things-you-should-never-do-with-essential-oils): Essential-oil mistakes that send people to hospital: phototoxic burns, undiluted use, ingestion and pets. What to avoid and why, with real cases. - [Essential Oils for Sleep: Building an Evening Wind-Down Routine](https://mahasutra.co/journal/essential-oils-for-sleep): Lavender, valerian, spikenard and neroli — what centuries of use and modern trials each tell us, and how to build an evening routine that holds. ## Candles & home fragrance - [Candle Tunnelling: Why It Happens and How to Fix It](https://mahasutra.co/journal/candle-tunneling): Why candles tunnel, how long the first burn should be, how to fix a tunnelled candle with foil, and burning habits that make candles last longer. - [Soy vs Coconut vs Paraffin Candle Wax: What the Research Says](https://mahasutra.co/journal/soy-vs-coconut-vs-paraffin-wax): Candle waxes compared: soy, coconut, paraffin, apricot, rapeseed, beeswax and stearin, plus what controlled emissions research found about each. - [Wooden Wick Candles: Why They Crackle and How to Burn Them](https://mahasutra.co/journal/wooden-wick-candles): Why wooden wick candles crackle, how they differ from cotton wicks, how to trim and light them, and how to fix flames that go out or smoke. - [Are Scented Candles Toxic? What the Research Actually Shows](https://mahasutra.co/journal/are-scented-candles-toxic): What scented candles release, what controlled emissions studies found, whether soy is safer, who should be careful, and how to burn candles more cleanly. - [Reed Diffuser Not Smelling? How to Make It Stronger](https://mahasutra.co/journal/reed-diffuser-not-working): Why reed diffusers stop smelling, how to make them stronger, how often to flip and replace reeds, where to place them, and how long they last. - [How to Make Your Home Smell Good: Every Method Compared](https://mahasutra.co/journal/how-to-make-your-home-smell-good): How to make your home smell good: removing odours, candles vs reed diffusers vs lava stones vs ultrasonic diffusers, and what to use in each room.